乳杆菌代谢产物对化脓性链球菌的抑制作用

【目的】分析乳杆菌代谢产物对化脓性链球菌的抑制作用。【方法】基于双层平板打孔法,通过测量抑菌圈大小来检测乳杆菌代谢产物对化脓性链球菌的抑菌作用;然后分别采用高效液相色谱法和4-氨酰安替比林法检测乳杆菌代谢产物中的有机酸和H2O2含量;最后,检测乳酸、乙酸和H2O2对化脓性链球菌的最小抑菌浓度(MIC)、最小杀菌浓度(MBC)。【结果】对化脓性链球菌的抑菌效果以植物乳杆菌KLDS1.0667最好,副干酪乳杆菌KLDS1.0342-1次之,瑞士乳杆菌KLDS1.0203抑菌效果最差;乳酸和乙酸产量KLDS1.0667>KLDS1.0342-1>KLDS1.0203;H2O2产量KLDS1.0203>KLDS1.0667>KLDS1.0342-1。在抑菌试验中,乳杆菌的发酵上清液经去除H2O2处理后抑菌圈直径都减小;将发酵上清液的p H调至7.0后均检测不到抑菌圈。结果表明,乳杆菌代谢产物中对化脓性链球菌起抑制作用的主要物质为有机酸和H2O2,其中乳酸是产生抑菌作用的最主要物质。乳酸、乙酸和H2O2对化脓性链球菌的最小抑菌浓度(MIC)分别为1.28、0.64和0.008 g/L,对化脓性链球菌的最小杀菌浓度(MBC)分别为5.12、2.56和0.032 g/L。【结论】乳杆菌可利用其代谢产物对化脓性链球菌产生抑制作用,主要抑菌物质为有机酸和H2O2。

Inhibition of Streptococcus pyogenes by lactobacilli metabolites

Objective] Inhibition of lactobacilli metabolites on Streptococcus pyogenes was analyzed. Methods] Three lactobacilli strains was grown in MRS broth overnight, then the culture supernatants were collected and evaluated for inhibitory activity. Inhibition was determined by measuring inhibition zone diameters with double plate punching method. Then HPLC and 4-Aminoantipyrine were used to determine the concentration of organic acids and H2O2 respectively in lactobacilli metabolites. Finally, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of lactic acid, acetic acid and H2O2 on S. pyogenes were determined. Results] Lactobacillus plantarum KLDS1.0667 had the strongest inhibitory effect among the three strains, followed by L. paracasei KLDS1.0342-1 and L. helveticus KLDS1.0203. L. plantarum KLDS1.0667 had the highest production of lactic acid and acetic acid, followed by KLDS1.0342-1 and KLDS1.0203. However, L. helveticus KLDS1.0203 had the highest production of H2O2, followed by KLDS1.0667 and KLDS1.0342-1. The diameters of inhibition zone all decreased after elimination of H2O2 in lactobacilli supernatants, and no obvious inhibition zones were detected when the pH of lactobacilli supernatants was adjusted to 7.0. The results indicated that organic acids and H2O2 were the main inhibiting substances in lactobacilli metabolites, further lactic acid was the most important inhibiting substance. MIC of lactic acid, acetic acid and H2O2 on Streptococcus pyogenes were 1.28, 0.64 and 0.008 g/L, respectively. MBC of lactic acid, acetic acid and H2O2 on Streptococcus pyogenes were 5.12, 2.56 and 0.032 g/L, respectively. Conclusion] The metabolites of lactobacilli could inhibit the growth of Streptococcus pyogenes, and the organic acids and H2O2 were the main inhibiting substances.